Lost sales revenue from counterfeit branded goods is a significant problem for the legitimate manufacturers. The use of counterfeit access cards results in significant theft loss from access to otherwise secured accounts, or results in the critical security breeches at secured military or industrial sites. While many forms of security marks have been devised to discourage counterfeiting, the degree of security afforded by any such mark is, of course, dependant on the cost of counterfeiting it relative to the value gained for having done so. Generally, any particular security mark declines in effectiveness over time because the specialty machinery and materials required to produce the security mark become lower in cost and more easily accessible. Eventually new security marks that are more difficult to counterfeit are required, leading to a classical “arms race” scenario between designers of security marks and the mark counterfeiters.
One way to categorize mark authenticity verification is by: a) human verification, or b) machine verification. Common examples of each include a) the human verifiable hologram embedded in the front face of most of today's credit cards, and b) the machine verifiable encrypted codes within the microcontroller chip embedded in the newer so called “smart cards”. Another way to categorize mark authenticity verification is by: a) local verification, or b) remote verification. With local verification, the mark must speak for itself. Local verification examples include seeing the holographic NFL label inside a baseball cap, or entering a PIN to match the information read from a magnetic strip by a card reader on a debit card. With remote verification, the validity or authenticity is not known until a remote database verifies the presented information, for example, by confirmation of an account number, a password, and funds available to make a purchase.
Methods used to aid human verification of a mark have primarily centered around the visual qualities of a label or tag. Beyond fancy printing, custom label stock, or molded tags, the most notable visual security mark common today is a custom hologram sticker having a stylized graphic of a company or organization logo to provide clear visual verification of authenticity. The most common type of hologram used is a metalized embossed polyester “rainbow hologram” well known on credit cards, software packages and professional sports branded articles. The rainbow hologram was originally developed by Polaroid Corporation, as disclosed in U.S. Pat. No. 3,633,989 granted Jan. 11, 1972 to Benton. Less common is the higher quality image of the volume reflection hologram with its fairly monochromatic images produced with photopolymers, such as the DuPont HRF-700 series, as disclosed in U.S. Pat. No. 4,996,120 granted on Feb. 26, 1991 to Smothers et al. and U.S. Pat. No. 4,942,112 granted Jul. 17, 1990 to Monroe et al. Unfortunately, the security of the rainbow hologram continues to fall prey to counterfeiters now finding it relatively easy to find companies offshore willing to copy and mass produce any image in a matter of days. However, for now the photopolymer based holograms appear to be relatively secure as the well patented photopolymers are treated as controlled materials. While fancy visual effects and 3-D logos may be helpful to people for evaluating the authenticity of an item, such human friendly security images haven't proven useful as a means for machines with optical scanners to independently determine the item's authenticity.
Numerous attempts have been made to secure documents with machine readable authentication marks. While everyday bar codes do a spectacular job at providing identity information, the mark itself is quite susceptible to duplication with a photocopy machine or with a desktop printer having a scanner, or one of hundreds of software packages available on the market for printing bar codes. Bar code scanners have been designed to detect and decode information from a light intensity pattern, but without any means for knowing if the bar code just scanned was on a box, on a book, printed with black ink, printed with blue ink, printed by a manufacturer in New York, or printed on the moon. A similar problem exists with the magnetic strip reader for credit, debit, and other ID cards. Although the magnetic strip will hold a fair amount of information, and is re-writable, the data on the magnetic stripe is easily copied or altered by hardware and software freely available on the market. Magnetic strip readers have been designed to detect and read a magnetic pattern, but without any means for knowing what card it was read from, if the information is fraudulent, or if the information is a counterfeit copy of the original.
To overcome the weakness in security of both bar codes and magnetic strips, some have incorporated an additional authentication code to help physically or logically machine validate the media or its data through requiring that the two code/data sources tie together in some way. As an example of the later, a card having both a magnetic recording strip and a linear series of diffraction grating patches on a strip, each reflecting light at a specific predetermined angle and requiring precise alignment in a scanner and wherein read data from each data source being compared to determine authenticity, is disclosed in U.S. Pat. No. 4,034,211 granted on Jul. 5, 1977 to Horst et al. An identification card having a magnetic strip with reflective marks over the magnetic strip is disclosed in U.S. Pat. No. 4,041,279 granted Aug. 9, 1977 to Foote. Similarly, a system of placing infrared reflection elements underlying a magnetic data stripe on a credit card is disclosed in U.S. Pat. No. 4,044,231 granted Aug. 23, 1977 to Beck et al. A card having both a magnetic strip and a reflection hologram with a linear series of reflective patches, each reflecting light at specific predetermined angle and requiring precise alignment in a scanner is disclosed in U.S. Pat. No. 4,641,017 granted on Feb. 3, 1987 to Lopata. A card having both a magnetic recording strip and a bar code, wherein read data from each are compared in an algorithm to determine authenticity is disclosed in U.S. Pat. No. 6,328,209 granted on Dec. 11, 2001 to O'Boyle. A label or card having a pattern of fluorescent dots, the locations of which are used to as a time-gate for reading the signature of diffractive/holographic reflections across the face of a card, requiring precise alignment with a scanner, and correlating data read with bar code or magnetic strip data, is disclosed in U.S. Pat. No. 6,535,638 granted on Mar. 18, 2003 to McGrew.
With the objective of making a covert code, or making a code copy machine proof, many have proposed systems utilizing the spectral limitations of the human eye in combination with inks that are invisible to the human eye, but fluoresce in the visible range when illuminated with ultraviolet (UV) or infrared (IR) light. Similarly, others have proposed systems that take advantage of inks that transmit or absorb light in the visible range, and do the opposite in the ultraviolet or infrared range. U.S. Pat. No. 3,279,826 granted Oct. 18, 1966 to Rudershousen describes a card having a UV fluorescent base material laminated with a material transparent in visible light, but which blocks UV light, and which has code markings or words made from or carved out of the UV blocking laminate. U.S. Pat. No. 3,829,662 granted Aug. 13, 1974 to Furahashi describes a card having a visibly black but infrared transparent layer under which is a base layer having a pattern of through holes which can only be detected with infrared light. U.S. Pat. No. 4,119,361 granted Oct. 10, 1978 to Greenway describes a card having a visibly black but infrared transparent layer under which is a linear arrangement of diffraction grating patches. U.S. Pat. No. 4,202,491 granted May 13, 1980 to Suzuki describes a data card containing data recorded with a fluorescent material that emits infrared rays when excited by infrared rays. U.S. Pat. No. 4,538,059 granted Aug. 27, 1985 to Rudland discloses an identification card with concealed coding made by infrared transparent windows of two widths providing binary coding readable by infrared radiation through material opaque to visible light. U.S. Pat. No. 6,203,069 granted Mar. 20, 2001 to Outwater describes a bar code printed in invisible ink that absorbs light in the UV or near-IR, and that has an IR fluorescent mark that emits visible light. U.S. Pat. No. 6,521,038 granted Feb. 18, 2003 to Yanagimoto, and U.S. Pat. No. 6,460,646 granted Oct. 4, 1995 to Lazzouni discloses visibly black but infrared reflecting inks to make it possible to print information which is not visible to the eye but is readable by infrared bar code scanners.
In addition to the savings of space, coaligned codes help increase the security of the media in two ways. First, in many cases an attempt to alter one of the codes disrupts the second, either physically or logically. Second, the copy resistance of the code is generally improved as at least one of the codes is implemented by an orthogonal technology. There are, for example, numerous methods referenced in prior patents relating to coaligned magnetic and optical codes. Coaligned bar codes utilizing wavelength discrimination also are present in the prior art. A multi-layered bar code made utilizing various non-interfering ink colors and reading them with specific wavelengths of light is disclosed in U.S. Pat. No. 5,502,304 granted Mar. 26, 1996 to Bearson. A bar code having the spaces between dark elements available for a possible UV fluorescent bar invisible to the human eye is disclosed in U.S. Pat. No. 6,354,541 granted Mar. 12, 2002 to Outwater. In matters of authentication, however, the security of colored inks is dubious today as they can be printed by any desktop color inkjet printer.
As various inventors have tried to make cards and labels more secure from copying while improving machine scanner authentication characteristics, the two characteristics of a hologram or diffraction grating used most often to advantage have been a) the ability to have a virtual mirror tilted at any angle while remaining physically flat and thin, and b) the ability to additionally incorporate holographic optical elements, such as lenses and optically encrypting distortion filters. Both of these characteristics require precise alignment of the scanner optics with the label or card to authenticate it, which is fine for a slot card reader, but would be a problem for the common hand-held bar code scanners used in retail and warehousing applications. U.S. Pat. No. 5,059,776 granted Oct. 22, 1991 to Antes discloses a diffractive bar code requiring precise alignment inside a scanner to benefit from the reflective bars. U.S. Pat. No. 5,101,184 granted Mar. 31, 1992 to Antes discloses a card with reflective patches having asymmetric diffraction gratings produced with partial microscopic mirror relief structures, pairs of which are 180 degrees different in the asymmetry and corresponding asymmetric reflection efficiency is used to verify authenticity of the mark. U.S. Pat. No. 5,306,899 granted Apr. 26, 1994 to Marom discloses a holographic correlation filter for examining a holographic image on a card, thus requiring precise position and angle relationships during reading. U.S. Pat. No. 5,920,058 granted Jul. 6, 1999 to Weber et al discloses that a holographic code image can be stored using a coded reference wave to distort the code image and thus hide it from human vision while a transform correlator reading device is able to reconstruct and detect the code image.
Holographic bar codes are known in the art. According to the broad definition of the term chosen for use herein, many of the patents in the foregoing paragraph describe forms of holographic bar codes, unfortunately, none of which are suitable for use with hand-held bar code scanners due to the requirement for precise optical alignment to successfully read the code. One way this has been overcome is to make a holographic image of a standard printed bar code wherein the white spaces have fairly omnidirectional diffuse reflecting characteristics, as disclosed in U.S. Pat. No. 5,422,744 granted on Jun. 6, 1995 to Katz et al. and U.S. Pat. No. 5,306,899 granted Apr. 26, 1994 to Marom. A card with an optically readable portion is incorporated into a magnetic machine readable stripe on the card wherein the optically readable portion can include a holographic representation of a bar code and wherein a check digit is derived by combining data from both optically and magnetically read portions is disclosed in U.S. Pat. No. 5,336,871 granted Aug. 9, 1994 to Colgate. Unfortunately, if the hologram produces a virtual image of a bar code, then even though standard bar code scanners can be easily aligned to read it, the security differentiation of it from a bar code printed on paper has vanished. Conversely, when the bar code is constructed of holographic of diffraction grating facets having very specific reflection angles, the security differentiation from a paper printed bar code may remain. However, the requirement for extremely precise alignment of the scanner precludes any real usefulness for applications requiring hand-held scanners.
Human readable characters have long been associated with bar codes, as exemplified by the ubiquitous UPC bar codes on grocery items (FIG. 1), and are most often used to provide an alternative for data entry when the bar code symbols are partly damaged and the bar code scanner fails to properly read them. In fact, a brief survey of bar coded objects and labels shows that it is more common than not to include a human readable number for these purposes. The more data-dense two dimensional bar codes, such as PDF417, Maxicode, and Datamatrix (FIG. 1), appear to rely heavily on other associated printed material, such as human readable address and order number, to provide sufficient backup should the contents of the bar code become unreadable, as opposed to having direct character per symbol translation. However, the human readable code has not been used as a true security feature in the authentication process.
In the art of bar code reading, utilization of multiple wavelengths has been disclosed by both Bearson and Outwater, as would be expected, for reading their bar codes having wavelength sensitive content. Many bar code reading disclosures include complex optical means to determine if the media on which the code is detected is in fact holographic. However, none have proposed multi-directional illumination as a means of ascertaining the three dimensional character of a hologram. Typically only a single light source is used, and when multiple sources are used from different directions, they still function as a single distributed light source, as opposed to having individual directions illuminated at separate times. For example, a bar code scanner head having a group of illuminating LEDs separately disposed to the right and left of the CCD photosensor optical path is disclosed in three U.S. patents; U.S. Pat. No. 5,291,009 granted on Mar. 1, 1994 to Roustaei, and U.S. Pat. No. 5,600,116 granted Feb. 4, 1997 to Seo et al., and U.S. Pat. No. 6,607,128 granted Aug. 19, 2003 to Schwartz et al. In each of the aforementioned patents, the LEDs are not separately illuminated, but rather are treated as a single extended illumination source.
The prior art holographic/diffractive bar code scanners either a) require precise alignment with the authentication mark to both read it and authenticate its media via detection of its unique holographic/diffractive optical properties, or b) require no special alignment with the authentication mark but are unable to authenticate its media because it is a virtual image replicating a paper and ink bar code. There is therefore an unmet need to both have a hand-held holographic bar code scanner without special alignment requirements to both read a holographic bar code and authenticate its media as being holographic.
The prior art coaligned code marks having magnetic strips and bar codes (of any kind) provide for both security and ID serialization, but are not suitable for hand-held scanner applications. The prior art coaligned wavelength sensitive printed bar code technology provides for ID serialization and hand-held scanner compatibility, but is substantially lacking in security today. Of further note, holographic bar codes are by their very nature heavily tooled and thus are compatible with mass production, but not ID serialization. There is therefore an unmet need to have a hand-held bar code scanner that can read a mark containing coaligned bar codes that provide both true security and capability for ID serialization.
The prior art uses alphanumeric characters adjacent to a bar code to provide a human readable representation of the code for backup when the bar code is damaged. With coaligned bar codes, the prior art presumption that the printed alphanumeric characters and the printed bar code should be directly tied is short sighted at best. There is therefore an unmet need in security applications to change the function of these alphanumeric characters to one of added security as opposed to simple redundancy.